This invention relates generally to truing the bores of rotary spindles, and more particularly concerns method and apparatus for effecting said truing by grinding the spindle bore while the spindle itself is rotating.
There are many advantages to grinding a spindle in place, one being the low down time. If the spindle were to be removed, more than likely the bearings and seals would, or at least should, be replaced. This becomes a procurement problem. Some seals and bearings can be long lead time procurement items. The spindle then needs to be sent out for grinding. This is also time consuming. All of this processing requires highly trained personnel, because in reassembly bearing preload and alignment is important.
There is another advantage to grinding in place, having to do with negating the run-out inherent in the bearings. By grinding in place, all items are taken into consideration and trued up.
U.S. Pat. No. 5,321,918 to Brian provides improved method and apparatus to enable grinding of a machine tool spindle in place, i.e., without removing it from the machine. That patent discloses a highly advantageous method of grinding the tapered bore of a rotary spindle, to true bore, and while the spindle rotates about a spindle axis, the steps of that method including:
a) providing structure including a master plate having a surface facing said bore, said surface having a predetermined boundary to define a center,
b) providing an angled slide on said structure, the slide being movable endwise relative to said spindle and at a predetermined angle to said axis, said angle corresponding to the spindle bore taper,
c) providing a rotary grinder on said angled slide to be movable endwise therewith while the grinder rotates,
d) adjusting said structure to bring said master plate surface into perpendicularity to said axis and to bring said center into coincidence with said axis, and
e) operating said grinder to grind said tapered bore as the spindle is rotated and as said angled slide is moved endwise at said predetermined angle to said structure.
There is need for further simplifying the above process, as for example to reduce weight and or bulk of the overall apparatus. This is particularly important in instances when the grinding apparatus must be transported to the site of a spindle or spindles to be ground, i.e. process simplification to enable apparatus portability is required.
Basically, the method of the invention concerns grinding the bore of a rotary spindle, said bore having a taper, to true said bore while the spindle rotates about a spindle axis, the steps that include:
a) providing a support attachable to a bore associated with said spindle,
b) providing an angled slide on said support, the slide being movable endwise relative to said spindle and at a predetermined angle to said axis, said angle corresponding to the spindle bore taper,
c) providing a rotary grinder on said angled slide to be movable endwise therewith while the grinder rotates,
d) adjusting said spindle to bring said spindle bore into position to be ground by said grinder as the grinder is moved on said angled slide relative to the bore, and as the spindle rotates,
e) operating said grinder to grind said tapered bore as the spindle is rotated and as said angled slide is moved endwise at said predetermined angle.
The above basic method takes advantage of accurate adjustability of the spindle so as to eliminate need for an additional slide carrying the angled slide and the rotary grinder, as disclosed in U.S. Pat. No. 5,321,918 referred to above.
Additional steps of the method may include adjusting the spindle in two directions, the first direction moving the spindle toward a guide surface extending in a second direction; and the spindle then being adjusted in that second direction to bring the spindle bore into position to be ground, as referred to. The axis of the spindle then coincides with the axis of a cone defined by the angled slide.
Further steps include providing a portable package which includes said support, the slide, the rotary grinder and the guide surface, and transporting the package to the location of the spindle and bore, for performing the steps a)-e) above.
In this regard the method may also include the step of removably attaching the support to the base, at the spindle site. Since need for a second slide for the support is eliminated, overall weight of the portable package is substantially reduced.
The basic apparatus for performing the method includes:
a) a support attachable to a bore associated with the spindle,
b) an angled slide on the support, the slide being movable endwise relative to said spindle and at a predetermined angle to said axis, said angle corresponding to the spindle bore taper,
c) a rotary grinder on said angled slide to be movable endwise therewith while the grinder rotates,
d) the spindle adjustable in two dimensions into a position enabling grinding of the spindle tapered bore by the grinder as the grinder is moved on said angles slide relative to said bore, and as the spindle rotates,
e) said grinder then operable to grind said tapered bore as the spindle is rotated and as said angled slide is moved endwise at said predetermined angle.
As will be seen, a guide surface is preferably attached to or integrated with the support, one of the two adjustment dimensions being a direction extending toward the guide surface (for example an X-direction), and the other of the two adjustment dimensions being a direction extending lengthwise of the guide surface (for example a Y-direction).
These and other objects and advantages of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following specification and drawings, in which: